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Blocker Water System

What EPA’s and CDC’s records show in this utility’s water: nitrate, arsenic and other regulated chemicals; lead and copper; and violations since 2016, with the certification that handles each result.

Serves
1,719 people
Connections
573
Water source
Groundwater
Based in
Sarepta, LA
County
Webster Parish
Owner
Private
The ZIP code it serves

71071

The short answer

1 result is above EPA’s legal limit, and 2 more are above the health goal. The worst: Total trihalomethanes (TTHM), above the legal limit. 3 health-based violations since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 2007 to 2026.

Total trihalomethanes (TTHM), haloacetic acids (HAA5) and nitrate: Louisiana’s yearly averages per water system, as CDC’s Environmental Public Health Tracking Network publishes them, 2020 to 2022, with EPA’s 2012 to 2019 file for earlier years.

Arsenic, fluoride, chromium (total) and uranium: EPA’s compliance monitoring file, samples taken from March 26, 2012 to June 4, 2018. Newer results are in the utility’s annual water quality report.

Above the legal limit1

Total trihalomethanes (TTHM)

Forms or is added in treatment

Above the legal limit

66.7ppb

Highest yearly average, 2020 to 2022

Averaged by year, the highest was 66.7 ppb, in 2022, below EPA’s legal limit of 80 ppb. That was also the latest year on file. EPA judges this limit at each sampling point, and recorded a violation for total trihalomethanes (TTHM) at this utility in 2025. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 49.6 ppb, in 2016.

What handles it

  • NSF/ANSI 53 look for “Trihalomethanes (TTHM) Reduction”
  • NSF/ANSI 58 look for “Trihalomethanes (TTHM) Reduction”

Above the health goal2

Lead

Comes from pipes, often your own

Above the health goal

1.0ppb

90th percentile, 2026

In the latest period, 9 in 10 homes sampled were at or below 1.0 ppb, below EPA’s action level of 15 ppb. The action level drops to 10 ppb on Nov. 1, 2027. EPA’s health goal for lead is zero.

What handles it

Arsenic

Comes from the source

Above the health goal

0.33ppb

Highest yearly average, 2012 to 2018

2018: not found

Averaged by year, the highest was 0.33 ppb, in 2012: below EPA’s legal limit of 10 ppb, but above its health goal of zero. Its highest single sample was 1.0 ppb. In 2018, the latest year on file, it wasn’t found in any of its three samples.

What handles it

  • NSF/ANSI 58 look for “Arsenic (Pentavalent)<=50 ppb Reduction”
  • NSF/ANSI 53 look for “Arsenic (Pentavalent)<=50 ppb Reduction”

Below EPA’s limits2

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

18.5ppb

Highest yearly average, 2020 to 2022

Averaged by year, the highest was 18.5 ppb, in 2022, below EPA’s legal limit of 60 ppb. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 18 ppb, in 2018.

What handles it

No certification claim covers this compound yet.

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.31ppm

Highest yearly average, 2012 to 2018

Averaged by year, the highest was 0.31 ppm, in 2018, below EPA’s legal limit of 4.0 ppm. Its highest single sample was 0.33 ppm. That was also the latest year on file.

What handles it

3 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Chromium (total)
  • Nitrate
  • Uranium

What handles it

A certification covers specific claims, not a whole standard. Look for these claims on the certifier’s listing, not the box. Wording varies a little: NSF writes “Lead Reduction,” WQA just “Lead.”

  • NSF/ANSI 53

    Claims: Trihalomethanes (TTHM) Reduction, Lead Reduction, Arsenic (Pentavalent)<=50 ppb Reduction

    For: Total trihalomethanes (TTHM), Lead, Arsenic

    Other certifiers’ wording: VOC Reduction; Arsenic (III) (50 ppb influent level)

  • NSF/ANSI 58

    Claims: Trihalomethanes (TTHM) Reduction, Lead Reduction, Arsenic (Pentavalent)<=50 ppb Reduction

    For: Total trihalomethanes (TTHM), Lead, Arsenic

    Other certifiers’ wording: Arsenic (Pentavalent)<=300 ppb Reduction; Arsenic (V) (300 ppb influent level)

At the tap, or for the whole house?

Lead and copper usually come from pipes and fixtures inside or near your home. A whole-house system sits where water enters, so it cannot catch what your own plumbing adds after it. For those, the filter that counts is the one at the tap. How whole-house systems compare.

Filters with those claims on a certifier’s listing

Disclosure: TapBuff earns a commission if you buy through some links on this page. It does not change which standard or filter we name. As an Amazon Associate, TapBuff earns from qualifying purchases. How TapBuff makes money

Compare five-year costs

The best water filters for lead, ranked

The best reverse osmosis systems, ranked

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2025 to June 30, 20250.089 MG/LResolved
Lead and Copper Rule RevisionsThe required inventory of lead service lines was not completed or submitted on time.EPA: LSL InventoryOct. 17, 2024—Resolved
Groundwater RuleA significant problem found in a state inspection was not fixed on time.EPA: Failure To Address DeficiencyNov. 11, 2021—Resolved
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 1 monitoring or reporting violation not shown.

What this report can’t tell you

  • Everything else. Total trihalomethanes (TTHM), haloacetic acids (HAA5) and nitrate results here are Louisiana’s yearly averages as CDC publishes them, from 2020 on, with EPA’s national file for 2012 to 2019. Arsenic, fluoride, chromium (total) and uranium come from EPA’s file alone, which ends in 2019. Blocker Water System’s own annual report, which it must send you every year, has newer results for those and the contaminants this page does not show.

  • Your own plumbing. Lead results are the 90th percentile across homes the utility samples. Your home’s service line, solder and fixtures decide yours. A certified lab test is the only way to know.

  • What it means for your health. This page reports what the records show and EPA’s limits and goals; it is not medical advice. If you are worried about a health effect, talk to a doctor or your local health department.

  • Anything after the latest data. SDWIS data is from 2026 Q3; UCMR 5 didn’t sample this utility; CDC’s yearly averages for Louisiana cover 2020 to 2022; EPA’s compliance samples are from March 26, 2012 to June 4, 2018.

Testing your own tap

Blocker Water System’s results are for the water it sends out. What your own service line, solder and fixtures add shows up only in a test of your tap, by a lab Louisiana certifies.

The lab Louisiana certifies closest to the area Blocker Water System serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • LDH Shreveport Regional Laboratory

    Shreveport, LA · about 34 miles

    Certified for bacteria

    (318) 676-7809

All 48 certified labs for Louisiana

Sources

PWSID LA1119002. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Webster Parish

All Louisiana utilities

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